Motorized lawn mowers are well-known for cutting grass or similar vegetation. These lawn mowers generally include a housing, a rotatable cutting element which is rotated in a cutting chamber inside the housing, and some type of motive means or power source for effecting rotation of the cutting element. The housings of such mowers have typically been designed to incorporate one or more grass discharge ports. The particles of cut grass are discharged through these discharge ports by the operation of the cutting element, i.e. the air flow pattern induced by rotation of the cutting element is effective to propel the grass particles outwardly through the discharge ports. Conventionally, many lawn mowers of this type have included a side discharge port which is located on the right side of the mower housing (taken from the perspective of one who is standing to the rear of the housing). Such a discharge chute usually sends the grass out a number of feet to the operator's right hand side during a grass mowing operation.
A desirable feature for rotary lawn mowers is the capability of bagging the cut grass particles. Older types of rotary lawn mowers used a flexible bag which was placed around a portion of the side discharge chute. The neck of the bag had a drawstring which could be tightened and cinched to releasably affix the bag on the side discharge port. In this type of mower, one could alternatively use either the side discharge port or the bagging attachment, but these elements were not simultaneously usable.
As the state of the art progressed, it was found to be desirable to have the bagging attachment location at the very rear of the machine. This enabled a more compact design since the bag no longer extended out to one side of the mower housing, but rather extended directly behind the housing into the space occupied by the mower handle. In turn, this enabled the mower to be used in more tightly confined spaces and to cut closer to an obstructing surface along the right side of the housing. This feature has, to the best of Applicant's knowledge, been provided simply by placing an appropriate rear bagging structure downstream of the typical side discharge port which is found on the right side of most mower housings. One example of such a rear bagging mower is the 21" Rear Bagger Mower which have been manufactured and marketed by The Toro Company of Minneapolis, Minn., which is the assignee of the present application.
While lawn mowers such as the 21" Rear Bagger are effective in cutting the grass and incorporate a number of desirable features, the fact that the side discharge port is located upstream of the rear bagging attachment presents a number of disadvantages. For one thing, grass will always be discharged through the side discharge port and will never reach the rear bagging attachment unless the side discharge port is affirmatively blocked. Thus, to convert the mower into a bagging mode of operation, it is necessary to install a suitable side cover over the side discharge port. This involves an extra step or operation for the operator and to this extent represents a disadvantage.
In addition, the grass receiving bags which have been heretofore used are effective but somewhat disadvantageous for the following reasons. The older type of bag having a flexible body with a drawstring at the neck is often difficult to empty when the bag is filled because the mouth of the bag is relatively small and the drawstring must first be loosened to allow the mouth to expand to the greatest possible extent. Other types of bags are known which use a flexible bag portion and a relatively rigid chute or mouth fixedly attached to the open end of the bag. This chute can be latched in place against a discharge port on the mower body. However, the rigid chute portions of the prior art bags usually have relatively small entrance openings. These openings are usually closed by a door or flap on the front of the chute which retains the clippings in the bag during bag removal from the housing. This bag door must be opened in order to dump the clippings from the bag. Because of the need for this door to retain the clippings, the prior art bags have been somewhat complex and more expensive to manufacture.
In addition to lawn mowers, mowing machines have been devised which are used for mulching purposes. In a mulcher, the particles of cut grass are desirably recirculated a number of times to cut the particles as finely as possible. These particles are then desirably driven downwardly to hide or embed the particles of cut grass in the uncut lawn. This prevents the unsightly appearance of grass clippings left on top of the lawn. In addition, the mulcher enables the grass clippings to decompose on the lawn in the manner of compost and become fertilizer for the lawn. In many instances, mulchers, because of their design, have been manufactured and sold separately from lawn mowers. Insofar as this represents a duplication of investment by the consumer, it is somewhat wasteful. It would instead be preferable that the same machine be able to effectively perform both as a mulcher and as a lawn mower.
The Toro 21" Rear Bagger noted above has been designed to operate both as a lawn mower and as a mulcher. To place this machine into a mulching mode, both the side discharge port and the rear discharge port associated with the rear bagging means are closed by using the side cover and by closing a rear door on the rear discharge port. In this configuration, the Toro Rear Bagger has an enclosed cutting chamber in which the particles of cut grass will be continuously circulated until they eventually are discharged downwardly onto the grass. However, since this machine has been designed with a relatively flat deck, particles of cut grass are sometimes not driven downwardly with sufficient force to effect a complete hiding of these particles in the uncut lawn. This is disadvantageous.
Various other mulchers utilize separate means for effecting a sufficient downward movement of the cut grass particles. One machine of which Applicant is aware utilizes a cutting blade having a cross-sectional shape with a number of corrugations therein. These corrugations ostensibly act to drive the cut grass particles downwardly into the grass. In addition, the assignee of this invention, in a co-pending U.S. patent application, Ser. No. 931,267, filed on Aug. 4, 1978, discloses a mulcher which basically utilizes a flat deck or housing. However, the underside of the housing in the cutting chamber utilizes a plurality of kickers or baffles for engaging the cut grass particles that are propelled through the cutting chamber. These kickers deflect the particles downwardly into the grass. While both of these machines effectively act as mulchers, they have a disadvantage in that some means, in addition to the basic housing configuration, must be used to effect the necessary downward movement of the cut grass particles.